Illumination device and liquid crystal display device

Abstract

An illuminator according to the present invention includes a backlight ( 110 ) for emitting light containing first and second polarization components having polarization directions which are orthogonal to each other; and a selective reflection polarizer ( 120 ) having a reflectance for the first polarization component which is higher than a transmittance for the first polarization component, and having a transmittance for the second polarization component which is higher than a reflectance for the second polarization component. The selective reflection polarizer ( 120 ) includes a transparent substrate ( 122 ) and a plurality of metal wires ( 124 ) arrayed on the transparent substrate ( 122 ). The ratio of a width of the metal wires ( 124 ) to a pitch of the metal wires ( 124 ) is greater than 30% and equal to or less than 42%, and the backlight ( 110 ) has a reflectance of 0.6 or more.

1. An illuminator comprising:
 a backlight for emitting light containing first and second polarization components having polarization directions which are orthogonal to each other; and 
 a selective reflection polarizer having a reflectance for the first polarization component which is higher than a transmittance for the first polarization component, and having a transmittance for the second polarization component which is higher than a reflectance for the second polarization component, wherein, 
 the selective reflection polarizer includes a transparent substrate and a plurality of metal wires arrayed on the transparent substrate; and 
 a ratio of a width of the metal wires to a pitch of the metal wires is greater than 30% and equal to or less than 42%, and the backlight has a reflectance of 0.6 or more. 
 
     
     
       2. The illuminator of  claim 1 , wherein the reflectance of the backlight is no more than 0.8. 
     
     
       3. The illuminator of  claim 1 , wherein the pitch of the metal wires is 200 nm or less. 
     
     
       4. The illuminator of  claim 1 , wherein the metal wires have a thickness of substantially 100 nm. 
     
     
       5. A liquid crystal display device comprising:
 a liquid crystal panel; 
 a backlight for emitting light containing first and second polarization components having polarization directions which are orthogonal to each other; and 
 a selective reflection polarizer interposed between the liquid crystal panel and the backlight, the selective reflection polarizer having a reflectance for the first polarization component which is higher than a transmittance for the first polarization component, and having a transmittance for the second polarization component which is higher than a reflectance for the second polarization component, wherein, 
 the selective reflection polarizer includes a transparent substrate and a plurality of metal wires arrayed on the transparent substrate; and 
 a ratio of a width of the metal wires to a pitch of the metal wires is greater than 30% and equal to or less than 42%, and the backlight has a reflectance of 0.6 or more.